"Short-acting" refers to medications or substances that have a quick onset of action and a relatively brief duration of effect. These are often used in medical treatments where immediate relief is needed, such as in the case of certain asthma inhalers or pain relief medications. In pharmacology, short-acting drugs typically reach their peak effectiveness within a short time after administration, often within minutes to hours. They are designed to be taken multiple times a day to maintain their therapeutic effects, making them suitable for conditions that require rapid and frequent intervention.